Pathological changes in the lymphatic system of patients with secondary upper limb lymphoedema

Secondary upper limb lymphoedema is usually caused by lymphatic system dysfunction. Diagnosis is primarily based on clinical features. However, there are no distinct diagnostic criteria for lymphoedema. Although conventional lymphoscintigraphy is a useful technique to diagnose the severity of lymphoedema, the resultant data are two-dimensional. In this study, we examined the pathology of lymphoedema using single photon emission computed tomography-computed tomography lymphoscintigraphy (SPECT-CT LSG), a new technique that provides 3-dimensional information on lymph flow. We observed lymph flow pathways in the subcutaneous and muscle layers of the upper limbs. A significant positive correlation was found between the dermal back flow (DBF) type and the visualization of lymph nodes around the clavicle (p = 0.000266), the type of lymph flow pathways and the visualization of lymph nodes around the clavicle (p = 0.00963), and the DBF type and the lymph flow pathway (p = 0.00766). As the severity of lymphoedema increased, the DBF appeared more distally in the upper limb and the flow into the lymph nodes around the clavicle decreased, whereas the lymph flow pathways in the muscle layer became dominant. These findings demonstrate the features of lymphoedema pathology and the functional anatomy and physiology of the lymphatic system without the need for cadaver dissection.

The warm colors indicate higher accumulation of contrast media of the tracer of lymph while the cold colors express fewer accumulation of lymph. This color coding is adopted to the following cine images.

Supplemental data 3b
Reconstructed PA view of the SPECT-CT LSG images of the same patient.
No dermal back flow is observed both in the forearm and in the upper arm; therefore, this case is considered to be type I of dermal back flow pattern.

Supplemental data 4a
Cine SPECT-CT LSG data of a patient with secondary upper limb lymphoedema on the right.
The lymph flow pathway of this patient is considered to be 'superficial dominant' because the accumulation of the tracer in the subcutaneous layer is higher than in the muscle layer at any level of the right upper limb. The same condition is observed on the opposite side in the left arm.

Supplemental data 4b
The reconstructed PA view of the SPECT-CT LSG images of the same patient.
Dermal back flow is observed both in the forearm and in the upper arm; therefore, this case is considered to have type III pattern of dermal back flow.

Supplemental data 5a
Cine SPECT-CT LSG data of a patient with secondary upper limb lymphoedema on the left.
The lymph flow pathway is categorized into the 'complex type' because the accumulation of the tracer is observed both in the subcutaneous layer and in the muscle layer except for the DBF part. Connections between a deep pathway and a superficial pathway are observed in the left upper arm. In addition, the lymph nodes around the clavicle are negative in these images.

Supplemental data 5b
The reconstructed PA view of the SPECT-CT LSG images of the same patient of data 5a.
Dermal back flow is observed in the forearm and in the upper arm around the elbow; therefore, this case is considered as having a type III pattern of dermal back flow.

Supplemental data 6b
The reconstructed PA view of the SPECT-CT LSG images of the same patient of data 6a.
As dermal back flow is observed only in the forearm, this case is considered to be type IV of dermal back flow pattern. The lymph nodes around the clavicle are not visualized in this image.

Supplemental data 7a
Cine SPECT-CT LSG data of a patient with secondary upper limb lymphoedema on the right.
The lymph flow pathway of the right upper limb is classified into 'superficial dominant' because the accumulation of the tracer is mainly observed in subcutaneous layer. Accumulation of the tracer is also obvious around the right clavicle.

Supplemental data 7b
The reconstructed PA view of the SPECT-CT LSG images of the same patient of data 7a.
As dermal back flow is observed nowhere, this case is regarded as having a type I pattern of dermal back flow. The lymph nodes around the clavicle are visualized in this image as the opposite side.

Supplemental data 8a
7 Cine SPECT-CT LSG data of a patient with secondary upper limb lymphoedema on the right.
The lymph flow pathway is categorized into 'deep dominant' because a high level of the accumulation of the tracer is observed near the bones or in the muscle layer. A little accumulation is seen around the left clavicle.

Supplemental data 8b
The reconstructed PA view of the SPECT-CT LSG images of the same patient of data 8a.
As dermal back flow is observed in the hand and around the wrist, this case is regarded as type V pattern of dermal back flow. Fewer lymph nodes around the clavicle are visualized in this image than in the image of the opposite side.